The present invention relates to a lens-fitted photographic film package, and more particularly to a lens-fitted photographic film package in which a photographic film, a taking lens and exposure elements with their associated structure are incorporated in a light-tight film case as an integral whole.
Lens-fitted photographic film packages provide many chances to enjoy oneself by conveniently taking pictures even when one has no camera. Such lens-fitted photographic film packages comprise, as an integral whole, a film case provided with a taking lens; simple mechanisms which include a film winding mechanism and an exposure mechanism with their associated structure incorporated in the film case; and a 110-size film cartridge or a film contained in a 35 mm-size film patrone pre-packaged in the film case, which can be sold wherever photographic film is sold. Such a lens-fitted photographic film package not only can be sold at a considerably low cost because there need be no provision of a film loading back cover, a film rewinding mechanism, a complicated exposure control mechanism and so forth that are provided in conventional cameras, but also provides photographers with convenience and fun when taking pictures because there is no need to load and unload a film.
Such a lens-fitted photographic film package, after the exposure of all frames of the film, is forwarded to a photo shop or photo laboratory without removing the film. There, the exposed film in the film cartridge is removed by rupturing the film package and then developed to make prints therefrom, while the film package without film is scrapped. The prints together with the developed film are returned to the customer.
However, it is difficult to make enlarged prints with a favorable image quality from 110-size film. For better image quality, it has been proposed to provide a lens-fitted film package including a 135-size roll film whose image size is 36.times.24 mm, which is the most popular for amateur photography. By incorporating a 135-size roll film in a film patrone defined by the International Standardization Organization (ISO code 1007: 1979 edition) in such a lens-fitted film package, the existing film processing systems can be utilized in their entireties for the lens-fitted film packages. In this case, a 135-size roll of film is withdrawn and rolled with its one end attached to a spool of the film patrone before being incorporated in the film package. In the film package, the rolled film and a patrone are housed in a film casing. Upon taking pictures, the rolled film is drawn into the film patrone one frame each exposure. When all the frames are exposed, the exposed rolled film is entirely within the patrone, which makes it possible to take the film patrone out of the film package in a daylight room without any film rewinding operation.
The most important requirement associated with such a lens-fitted film package using a 135-size film is to hold the film accurately in the exposure position. However, because the film package tends to deform upon the application of external force, it is a bit difficult to maintain the film flat in the focal plane. For avoiding the influence of external force on the film in the film package, a pressure plate similar to those provided in conventional cameras can be incorporated in order to hold the film accurately in the exposure position. However, from the standpoint of low manufacturing cost of such a lens-fitted film package, the provision of a pressure plate is not advantageous.